1. Field of the Invention
This invention relates, in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves pressure balanced poppet valves for couplings wherein passages are positioned to allow connection or disconnection of the coupling and opening and closing the poppet valves in each member without substantial fluid pressure exerted axially against the face of each poppet valve.
2. Description of the Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male and a female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore in the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members.
Problems arise with the use of hydraulic couplings in relatively high pressure systems due to the high axial forces imposed on the male and female members during the coupling operation and during their use. In such couplings, it is necessary for the fluid force opposing the face of the male or female member to be overcome and the fluid force on each valve member to be overcome before fluid communication is established between the members. In a relatively high pressure system, high forces imposed on the members and the valves in the members may render the connection of the male member very difficult. Also, during use, fluid pressure is exerted between the male and female members in such as way as to tend to separate them. The force necessary to join the members, and open the valves in each member, and the resultant tendency of the body members to separate and urge the valves closed are characteristic problems in the prior art. High pressure systems and undersea applications also experience problems associated with sealing the junction between the male and female members.
Ideally, hydraulic couplings should, as far as possible, be pressure balanced, so that fluid pressure does not hinder connection, urge separation of the male and female members, or urge the valves towards the open or closed position. Preferably, to prevent loss of fluid during coupling or uncoupling, the valve means in each member opens automatically on coupling and closes automatically on uncoupling. Finally, the coupling should employ seals which can withstand high pressures as well as the corrosive effects of undersea or other adverse environments. The present invention solves all of these needs and requirements.
In U.S. Pat. No. 4,754,780 to Robert E. Smith III, a pressure-balanced hydraulic coupling is disclosed, wherein fluid communication between the male and female coupling members is through radial fluid passages in the members. In U.S. Pat. No. 4,694,859 to Robert E. Smith III, an undersea hydraulic coupling and metal seal is shown. The metal seal is ring-shaped and is pressure energized to seal radially between the female member and the outer surface of the male member. In U.S. Pat. Nos. 4,832,080 and 5,099,882 to Robert E. Smith III, pressure-balanced hydraulic couplings with metal seals are disclosed. Like the coupling in U.S. Pat. No. 4,754,470, fluid communication is through radial fluid passages in the male and female members. Metal seals are positioned between the circumference of the male member and the central bore of the female member, such that the radial fluid passages are between the seals. U.S. Pat. Nos. 4,754,780, 4,694,859, 4,832,080, and 5,099,882 are incorporated herein by reference.